This invention relates to a ball, and to a method of manufacturing a ball, and more particularly relates to a ball which may be thrown to deviate from an expected trajectory.
In ball games such a cricket and baseball, the ability to “swing” or “curve” a ball is highly prized. To be able to move a ball from a “normal” trajectory usually takes a degree of skill. For those not sufficiently skilled, or for those who wish to play or train with a ball that will deviate without the bowler or pitcher having sufficient skill, a special ball is required.
Australian Patent No. 588223, and equivalent U.S. Pat. No. 4,874,169, both to Peter Graham Litchfield, describe a ball designed to deviate in flight when bowled as in the game of cricket or thrown as in the game of baseball. In this specification, hemisphere 12 has the same meaning as first hemisphere 12 referred to in the abovementioned patents, hemisphere 14 has the same meaning as second hemisphere 14 referred to in the abovementioned patents, and line 16 between hemispheres 12 and 14 has the same meaning as line 16 referred to in the abovementioned patents.
Hemisphere 12 is the ‘fast’ side of the ball and it is therefore desirous to achieve minimum aerodynamic drag on this hemisphere. The abovementioned patents well describe how this may be achieved. Hemisphere 14 is the ‘slow’ side of the ball and it is therefore desirous to achieve maximum aerodynamic drag on this hemisphere. The abovementioned patents describe this hemisphere as being either generally smooth, or generally rough, or as having a felt like texture thereon, and all such embodiments have been shown to be effective.
If any ball in the above mentioned patents, or any ball in this specification, is propelled along the plane of line 16, the ball will deviate from that plane in the direction of hemisphere 12. The ball need only have normal back spin imparted on release, no other ‘special’ spin is required or desired to be imparted to the ball.
In the game of cricket, a conventional cricket ball has a stitched seam along the line 16 between hemispheres 12 and 14 of any ball in the abovementioned patents. The abovementioned patents state that “A simulated seam could be included, as long as it coincided with line 16 it would not adversely effect the performance of the ball.” A simulated cricket ball seam (raised or depressed) can therefore be included on any embodiment of a ball claimed in the abovementioned patents, without adversely affecting the performance of the ball.
In the game of baseball, a conventional baseball has a stitched seam, which is raised, but not parallel to any line between two hemispheres. Therefore, the seam does adversely affect the performance of the ball when trying to achieve deviation by projecting such a ball in the manner described in the abovementioned patents. The seam forms the “dumbbell” shaped portions of the ball, and give a baseball its unique appearance and feel.
In Australian Patent No. 588223, it is stated that: “A ball may have a simulated seam in the pattern of actual seams on baseballs or tennis balls and such could incorporate the depressions or protrusions”. Although this is true, simulated raised baseball type seams do not adapt well to balls described in the aforementioned patents for the following reasons.
Firstly, although the raised seam somewhat constitutes the disturbance or “two-level” effect required on hemisphere 12, it is also mirrored on hemisphere 14, and therefore any tendency for the ball to deviate in flight is neutralised. Secondly, the appearance and feel of the raised seam is lost if hemisphere 14 is provided with moulded homogenous roughness as outlined in the abovementioned patents.
Modified tennis balls can be employed for hemisphere 14, but the look and feel of a baseball is not achieved. Furthermore, the desired raised seams are not present on hemisphere 14 of tennis balls unless they are subsequently bonded onto the outer surface. This further complicates difficulties already experienced when trying to manufacture hybrid balls of this general type. That is, half tennis ball and half rubber (or synthetic) ball. Balls of this type also have inherent structural weakness at the join line between the two hemispheres, and have a tendency to go “out of shape”.
It is an object of this invention to provide an improved or alternative ball of the general type described in Australian Patent No. 588223 and U.S. Pat. No. 4,874,169, including an improved simulated baseball. It is also an object of the invention to provide a cost-effective means of producing such a ball.